A storage device relates to a disk storage system in which two or more disk drives are installed. A storage device includes a controller module (hereinafter, referred to as “CM”) that writes the data transmitted from a host into a disk drive.
A storage device also includes a BUD (Backup Utility Device) inside and outside the CM. As an example of the BUD, a HDD (Hard Disk Drive), an SSD (Solid State Drive), and a USB (Universal Serial Bus) memory device are used. The records inside the device such as a device log and firmware archive are stored in the BUD.
The data in the BUD is made redundant by two or more BUDs according to each purpose of use (requirement of system performance). The data consistency and redundancy maintenance among BUDs is realized by an equivalence control unit of the CM. As a result, the mutual equivalence of the data among BUDs may be maintained.
The following technique is known as a recovery technique of a storage device. In this known technique, when an OS (Operating System) starts operating, a service program loads a metadata record/judgment/repair unit into the control unit of a storage device. When a data lost error is detected by the control unit, the metadata record/judgment/repair unit performs the following processes. Specifically, the metadata record/judgment/repair unit judges whether the error occurrence address is in a metadata area or in a file data area based on the error occurrence address of a data lost error of the data storage unit and the metadata read from the metadata backup unit. When the error occurrence address is in the metadata area, the metadata record/judgment/repair unit restores the metadata area of the data storage unit with the metadata area backup data of the metadata backup unit.
Patent Document 1: Japanese Laid-open Patent Publication No. 2005-149248